1. Technical Field
This invention relates generally to reconditioning rechargeable batteries, and more specifically to an adaptor for a non-smart battery that facilitates reconditioning in a smart charger.
2. Background Art
When a nickel-based rechargeable battery is placed in a charger before it is completely discharged, it may lose some of its capacity due to a phenomenon known as the “memory effect”. In other words, if a battery is repeatedly placed in a charger prior to being completely “dead”, the battery will “die” more and more quickly in the future. In some cases, a fully charged battery that originally lasted for four hours might die after only one hour.
This memory effect, or voltage depression, is particular to nickel chemistry batteries. In nickel batteries, the storage capacity—or in technical terms the “energy versus time curve”—changes based upon discharge patterns. The good news is that the memory effect can be nearly eliminated by fully discharging the battery at a nominal current. This type of full discharge is called “reconditioning”.
To keep a battery at original capacity, the battery needs to be reconditioned whenever the discharge time, i.e. the usable time of the battery, has become reduced. Commonly assigned U.S. Pat. No. 6,433,511, entitled “Method and Apparatus for Manually Reconditioning a Battery Without a Switch”, incorporated herein by reference in its entirety, teaches a “smart” charger that automatically reconditions batteries at the appropriate time. (The term “smart” refers to a charger with a microprocessor, wherein the microprocessor is capable of reading data from the battery pack and making charging decisions based upon that data.) The smart charger in the '511 patent also allows manual reconditioning by rapidly removing and reinserting the battery into the charger.
The system of the '511 patent works well so long as the battery that is inserted into the charger includes at least a memory device with which the smart charger can communicate. A memory device alerts the charger as to battery type and state of charge, as well as telling the charger that a reconditioning path is present in the battery (some batteries include blocking diodes that prevent reconditioning). If there is no memory device in the battery, the charger will not be able to properly recondition the battery.
Smart batteries and chargers are relatively new devices. Consequently, many batteries on the market are simply that: batteries. They include no microprocessors, no fuel gauging circuitry and no memory devices. As such, they are not capable of being reconditioned in a smart charger. Such batteries therefore are very susceptible to memory effects.
Therefore a need exists for a means of reconditioning non-smart batteries in smart chargers.